Equilibrium constants determined by ICR methods will be used to obtain the energies of hydrogen-bond attachments of molecules to cations and anions. These results will be used to critically test structural theories. Further, in combination with known gas phase acidities and basicities these results will be used to critically test the extent to which these attachments of single molecules to each available protonic site in the cation or each active lone-pair site in the anion can quantitatively account for the effect of water and other solvents on protonic acid-base equilibria. Solution hydrogen-bond formation constants and hydrogen-bonding effects of pure solvents will be determined with ionic and neutral solutes using F-nmr and C-nmr methods. In collaborative studies, the measurement of intensities of Raman scattering will be applied to the study of structural effects on protonation insolution and on hydrogen-bonding between ions and solvents or counterions. Biological important hydrogen-bond acceptors and donors are given emphasis.